/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.visitor;

import proguard.classfile.*;

/**
 * This <code>ClassVisitor</code> delegates its visits to program classes to another given <code>ClassVisitor</code>,
 * but only when the class version number of the visited program class lies in a given range.
 *
 * @author Eric Lafortune
 */
public class ClassVersionFilter implements ClassVisitor {
    private final int minimumClassVersion;
    private final int maximumClassVersion;
    private final ClassVisitor classVisitor;

    /**
     * Creates a new ClassVersionFilter.
     * 
     * @param minimumClassVersion the minimum class version number.
     * @param classVisitor the <code>ClassVisitor</code> to which visits will be delegated.
     */
    public ClassVersionFilter(int minimumClassVersion, ClassVisitor classVisitor) {
        this(minimumClassVersion, Integer.MAX_VALUE, classVisitor);
    }

    /**
     * Creates a new ClassVersionFilter.
     * 
     * @param minimumClassVersion the minimum class version number.
     * @param maximumClassVersion the maximum class version number.
     * @param classVisitor the <code>ClassVisitor</code> to which visits will be delegated.
     */
    public ClassVersionFilter(int minimumClassVersion, int maximumClassVersion, ClassVisitor classVisitor) {
        this.minimumClassVersion = minimumClassVersion;
        this.maximumClassVersion = maximumClassVersion;
        this.classVisitor = classVisitor;
    }

    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass) {
        if (programClass.u4version >= minimumClassVersion && programClass.u4version <= maximumClassVersion) {
            classVisitor.visitProgramClass(programClass);
        }
    }

    public void visitLibraryClass(LibraryClass libraryClass) {
        // Library classes don't have version numbers.
    }
}
